The present invention relates generally to an electronic package, and more particularly to a method and apparatus for securing an electronic package to a circuit board.
Electronic packages typically include a number of integrated circuits which are housed within a plastic or ceramic package. Such packages, hereinafter referred to as "electronic packages", are generally rectangular or square in shape and include a plurality of conductive pads on a bottom surface thereof. The conductive pads may be arranged in a grid-like pattern to increase number or density of the conductive pads which may be included in the electronic package. One such type of grid-like pattern arrangement is referred to as a ball grid array package. In a ball grid array package, a finely-pitched matrix of spheroid- or ball-shaped conductive pads extend outwardly from the bottom surface of the electronic package.
A circuit board, such as a printed circuit board or a printed circuit assembly, to which the ball grid array package is to be mounted includes a corresponding number of conductive pads which are arranged in a similar matrix as the matrix of ball-shaped conductive pads included in the ball grid array package.
In order to mount the ball grid array package to the circuit board, a small quantity of a conductive metal alloy such as solder is placed on the conductive pads of the circuit board prior to placing and aligning the conductive pads of the ball grid array package thereon. Thereafter, the circuit board and the ball grid array package thereon are heated to a temperature which is greater in magnitude than the melting point of the solder thereby fusing the ball-shaped conductive pads of the ball grid array package to the conductive pads of the circuit board.
Although soldering the ball grid array package to the circuit board yields a strong, reliable mechanical and electrical connection, it may be undesirable if it becomes necessary at a later time to remove the ball grid array package from the circuit board. In particular, if it becomes necessary to repair or replace the ball grid array package that is soldered to the circuit board, the circuit board must again be heated to a temperature which is greater in magnitude than the melting point of the solder in order to remove the ball grid array package from the circuit board. Such re-heating of the circuit board may reduce the useful life of both the circuit board and the various other components secured thereto.
Soldering the electronic package is particularly undesirable during the development stages of a given electronic assembly. This is true since the various integrated circuits within the ball grid array package may require several design iterations during the development thereof. Hence, upon each occasion that the design of one of the integrated circuits is altered, the ball grid array package must be unsoldered, and a ball grid array package containing a revised version of the integrated circuit is thereafter soldered to the circuit board. As described above, such unsoldering and re-soldering may damage and/or destroy the circuit board and the other components secured thereto, thereby disadvantageously lowering yields and raising costs associated with the development of the electronic assembly. Moreover, the position of the electronic package on the circuit board and/or the configuration of the electronic package itself may prevent the electronic package from being removed from the circuit board in manner which does not irreparably damage the circuit board and/or the other components secured thereto. Hence, upon each occasion that the design of one of the integrated circuits is altered, the entire electronic assembly may have to be discarded thereby disadvantageously raising costs associated with the development of the electronic assembly.
To this end, a number of electronic package securing mechanisms such as sockets or other similar mechanical clamps have been developed to hold or otherwise secure an electronic package to a circuit board without the use of solder on the conductive pads of the electronic package. However, many of the electronic package securing mechanisms which have heretofore been designed are mechanically complex. Moreover, many of the electronic package securing mechanisms which have heretofore been designed require precision placement and alignment thereof on the circuit board by the use of expensive automated placement machines such as "pick and place" machines.
What is needed therefore is a method and apparatus for securing an electronic package to a circuit board which does not require the use of solder. In addition, what is needed is a method and apparatus for securing an electronic package to a circuit board which is relatively simple and inexpensive. Moreover, what is needed is a method and apparatus for securing an electronic package to a circuit board which does not require the use of automated placement machines. What is further needed is a method and apparatus for securing an electronic package to a circuit board which enables fast and simple removal and replacement of the electronic package.